<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
        body {
            background-color: #ccc;
        }
        
        .father {
            margin: 200px auto;
            position: relative;
            background-color: #6b6464;
            box-sizing: border-box;
            border: 1px solid #000;
        }
        
        .child {
            position: absolute;
            top: 10px;
            left: 10px;
            width: 180px;
            height: 180px;
        }
        
        .border {
            position: absolute;
            background-color: #fff;
        }
        
        .border_left_top {
            width: 60px;
            height: 10px;
            left: -5px;
            top: -5px;
        }
        
        .border_top_left {
            width: 10px;
            height: 50px;
            left: -5px;
            top: 5px;
        }
        
        .border_right_top {
            width: 60px;
            height: 10px;
            right: -5px;
            top: -5px;
        }
        
        .border_top_right {
            width: 10px;
            height: 50px;
            right: -5px;
            top: 5px;
        }
        
        .border_left_bottom {
            width: 60px;
            height: 10px;
            left: -5px;
            bottom: -5px;
        }
        
        .border_bottom_left {
            width: 10px;
            height: 50px;
            left: -5px;
            bottom: 5px;
        }
        
        .border_right_bottom {
            width: 60px;
            height: 10px;
            right: -5px;
            bottom: -5px;
        }
        
        .border_bottom_right {
            width: 10px;
            height: 50px;
            right: -5px;
            bottom: 5px;
        }
    </style>
</head>

<body>
    <div class="father" style="width: 200px; height: 200px">
        <div class="child">
            <div class="border border_left_top"></div>
            <div class="border border_top_left"></div>
            <div class="border border_right_top"></div>
            <div class="border border_top_right"></div>
            <div class="border border_left_bottom"></div>
            <div class="border border_bottom_left"></div>
            <div class="border border_right_bottom"></div>
            <div class="border border_bottom_right"></div>
        </div>
    </div>
</body>

</html>